Preparation of organotin-trihalides



United States Patent 3,340,283 PREPARATION OF ORGANOTIN-TRIHALIDES CarlR. Gloskey, Stirling, NJ., assignor to M & T Chemicals Inc., New York,N.Y., a corporation of Delaware No Drawing. Filed May 20, 1964, Ser. No.368,982 14 Claims. (Cl. 260-4291) This invention relates to a novelprocess for preparing organotin compounds. More specifically, it relatesto a novel technique for the attainment of high yields of organotinproducts.

It is well known to those skilled-in-the-art that various organotincompounds having the formula R SnX (wherein the sum of a and b is 4) maybe prepared by various reactions including those wherein an alkyl halideRX may be reacted with metallic tin or with certain tin compounds, suchas tin tetrahalide. Although these reactions may find a Wide commercialuse, they are particularly useful when used to produce high yields ofcompounds R Sn and R SnX. Certain selected reactions of this type mayalso yield amounts of R snX ranging from minimal to low. It is howeverwell known that there is no commercially available technique for theproduction of RSnX compounds in high yields, at moderate cost; andaccordingly when such compounds are desired, it is necessary to preparethem indirectly from other organotin compounds or to use methods ofpreparation which are inordinately expensive and thereforenon-commercial.

It is an object of this invention to set forth a novel process for thepreparation of organotin compounds. It is a further object of thisinvention to set forth a novel process particularly characterized by theproduction in high yield of organotin compounds having the formula RSnXOther objects will be apparent to those skilledin-the-art frominspection of the following description.

In accordance with certain of its aspects, the method of this inventionfor preparing organotin compounds RSnX by the reaction SnX +RX RSnXwherein R is a hydrocarbon group, Sn is tin, and X is an active halogenmay comprise reacting anhydrous SnX with RX in the presence of an aminecatalyst in a reaction mixture thereby forming RSnX maintainingsubstantially equivalent amounts of SnX and RX in said reaction mixtureduring said reaction; maintaining said reaction mixture at 100250 C. andautogenous pressure during said reaction; and separating RSnX from saidreaction mixture.

In practice of the process of this invention, it may be possible toreact SnX with RX in the presence of amine catalyst to form RSnX Thehydrocarbon halide RX which may be used in the process of this inventionmay be a compound wherein R may preferably be a hydrocarbon moiety,preferably selected from the group consisting of alkyl, aryl, alkaryl,aralkyl, cycloalkyl, etc. and X may be seen an active halide preferablyselected from the group consisting of bromide and chloride. When R isalkyl, it may be methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl,sec-butyl, amyl,

octyl, decyl, octadecyl, etc. When R is alkaryl, it may typically betolyl, xylyl, etc. When R is cycloalkyl, it may typically be cyclohexyl,cycloheptyl, methylcyclohexyl, etc. When R is aralkyl, it may typicallybe benzyl, wphenylbutyl, etc. When R is aryl, it may typically bephenyl, naphthyl, etc. The preferred R group may be lower alkyl i.e.alkyl groups having 1-10 carbon atoms. Inertly substituted R groups maybe employed.

Illustrative preferred compounds RX which may be used in practice ofthis invention may include the following chlorides and the correspondingbromides: methyl chloride, ethyl chloride, n-propyl chloride, i-propylchloride, n-butyl chloride, hexyl chlorides, octyl chlorides, dodecylchlorides, octadecyl chlorides, tolyl chlorides, xylyl chlorides,cyclohexyl chloride, cycloheptyl chlo- 'ice ride, benzyl chloride,w-phenylethyl chloride, phenyl chloride, etc.

The preferred hydrocarbon halide RX used in the practice of thisinvention may be n-butyl chloride.

Substantially all of these halide compounds may be liquid at roomtemperature; and they may typically have boiling points, depending uponthe nature of the R group, which may permit maintenance of the reactionmixture in the liquid phase during the reaction.

The compound SnX which may be used in the practice of this invention maytypically be stannous chloride SnCl stannous bromide SnBr etc. Thepreferred compound which may be employed will be stannous chloride. Itis preferred that the X in the compound SnX be the same as the X in RX;and preferably X will be chlorine.

In practice of this invention the compound SnX as used will preferablybe anhydrous, i.e. preferably contain less than about 0.1% water.

It is preferred to carry out the reaction using substantially equivalentquantities of SnX and RX reactants; however, it may be desirable to usean excess of RX to gain fluidity. Typically the molar ratio of thesextwocomponents may be 1.02.0, and most preferably it will be maintained atabout 1-1. Operation in this region may permit attainment of maximumyield of the desired selected product RSnX The catalyst which may beemployed in the course of this reaction may be an amine includingaliphatic and aromatic primary, secondary, and tertiary amines. Typicalamines which may be employed in practice of this invention may becompounds having the formula R N wherein O-2 R groups may be hydrogenand at least one of the R groups may be preferably selected from thegroup consisting of alkyl, aryl, alkaryl, aralkyl, cyclo alkyl, alkenyl,acyl, etc. It will be apparent that two of the R groups may becyclicized to form amines, the nitrogen atom of which is a component ofa ring as e.g. in pyridine. It is also apparent that diamines andpolyamines may be employed.

It is preferred that the amine compound which is to be employed as acatalyst in this reaction be one which is liquid at normal ambienttemperatures of 2030 C. and that the amine may be one which may be inliquid phase at the temperature and pressure prevailing in the reactionas hereinafter set forth.

Typical amines which may be employed in the practice of this inventionmay include: methyl amine, ethyl amine, n-propyl amine, n-butyl amine,i-butyl amine, n-arnyl amine, hexyl amine, octyl amine, allyl amine,cyclohexyl amine, benzyl amine, p-toluidine, aniline, p-methyl aniline,w-phenylethyl amine, ethylene diamine, p-chloro aniline; etc.

Dimethyl amine, diethyl amine, di-n-butyl amine, di-namyl amine, dihexylamine, dioctyl amine, diallyl amine, dicyclohexyl amine, dibenzyl amine,n-methyl ethyl amine, nmethyl aniline, n-ethyl aniline, hexamethylenetetra- .mine, n-methyl naphthylamine; etc.

Trimethyl amine, triethyl amine, tri-n-propyl amine, tri-n-butyl amine,trihexyl amine, triallyl amine, tn'cyclohexyl amine; etc.

Aniline, p-toluidine, o-toluidine, m-toluidine; etc.

Benzyl amine; etc.

Pyridine, Z-methyl pyridine, 3-methyl pyridine, 2-ethyl pyridine,3-ethy1 pyridine, quinoline, 6-methoxy quinoline, etc., a-picoline,fi-picoline, gamma picoline.

Inertly substituted amines including p-chloro aniline, etc. may beemployed.

The preferred amines which may be used in practice of this invention mayinclude triethylamine, aniline, pyridine, and n-butylamine.

It will be apparent to those skilled in the art that these amines may beused in the form of a salt with e.g. a

3 hydrocarbon halide such as the alkyl halide RX. Typical of suchmaterials may be aniline hydrochloride; or quaternaries typified by thecompound formed e.g. by the reaction of n-butyl amine and n-butylchloride, i.e., n-butyl ammonium chloride; phenyl methyl ammoniumchloride; etc. 7

In practice of this invention, these amines may be present in thereaction mixture in catalytic amount, typically 0.012%, most preferably0.l1%, and typically 0.5 mole percent of the amount of SnX compoundpresent.

The process of this invention .may be carried out by addition to areaction vessel of the charge compounds SnX and RX, together withcatalytic amount of amine. In a preferred embodiment of this invention,the reaction may be carried out in the presence of appropriate inertdiluent e.g. solvent. It is a feature of this invention that thereaction may be effected very smoothly to give high yields of desiredproducts by use of solvent. Typical diluents or solvents which may beemployed may include inert liquids having a boiling point of 75 250 C.including aliphatic hydrocarbons such as hexane, heptane, octane, etc.;aromatic hydrocarbons such as benzene, toluene, xylene, etc.;cycloaliphatic hydrocarbons such as cyclohexane, cycloheptane, etc.Mixtures of solvents may be used.

The solvent to be employed may preferably be added to the reactionvessel in amount sutficient to establish a substantial excess thereof,whereby the reaction mixture may be substantially entirely liquidphase-containing solid including e.g. SnX when this compound may not besoluble in the diluents and reactants. Typically the solvent may bepresent in amount of 100%, say 50-75%, preferably 50% of solvent byweight of total reactants.

Reaction may be effected by heating the reaction mixture typically totemperatures of 100250 C., preferably 200-225 0, say 200C. In thepreferred embodiment of the process of this invention, heating may becarried out under autogenous pressure, i.e. the reaction vessel may besealed at the beginning of the heating step and pressure generatedtherein may correspond to that of the reactants and the reactionproducts. The reaction mixture may be maintained under theseconditionsfor 2-10 hours, typically 4-8 hours, say about 5 hours. Itwill be apparent to those skilled in the art that the pressure developedwill depend upon the vapor pressure of the reaction mixture; and it willalso be apparent that the time of reaction may depend upon the pressureand temperature. Higher pressure and temperature may permit the reactionto be carried out in shorter periods of time and vice versa. Thereactants may react to give high yields of RSnX At the conclusion of thereaction, the reaction mixture may be cooled to 20-30 C. and residualunreacted stannous halide RSnX may be separated from the reactionmixture as by decantation, filtration, centrifuging, etc.

The reaction mixture may then be distilled to separate volatilehydrocarbon halides RX together with solvent which may be present. Inthe preferred embodiment, distillation may be carried out up to atemperature of typically slightly above (e.g., -20 C. above) the boilingpoint of the solvent at the pressure of distillation. This may permitselective removal from the reaction mixture of the solvent and leavesbehind an organotin mixture typically containing primarily RSnX As willbe apparent, the process of this invention permits attainment of highyield of RSnX compounds.

Separation of the other organotin components in the reaction mixture maybe carried out as desiredtypically by distillation, solvent extraction,or other techniques which may be well known to those skilled in the art.Separation e.g. by distillation may also remove any other materials suchas residual amounts of RX which may be present in the reaction mixture,at this time; and SnX present in the organotin mixture may be recoveredas residue if not earlier removed as by filtration.

Practice of this invention may be apparent to those skilled in the artby reference to the following examples wherein all parts are parts byweight unless otherwise specified.

EXAMPLE 1 189.6 parts (1 mole) of anhydrous stannous chloride and 138.9parts (1.5 moles) of anhydrous normal butyl chloride may be added to areaction vessel together with 0.46 part (0.005 mole) of anilinecatalyst.

The reaction vessel may then be sealed and heated to 200 C. for 5 hoursduring which time the pressure'inside the vessel may be autogenous. Atthe end of this time, the reaction vessel may be cooled to ambienttemperature of 20-30 C. and the contents removed and filtered toseparate any solid material contained therein, the solid being Washedwith anhydrous butyl chloride, which may then be combined with thefiltrate.

The combined filtrate on distillation may yield (a) 64 parts of fore-runwhich may contain 60 parts of butyl chloride, and 4 parts of butyltintrichloride;

(b) A distillate containing 200 parts of butyltin trichloride boiling at120 C. at 10 mm. Hg and;

(c) A residue of 40 parts of stannous chloride.

The yield of butyltin trichloride (Sn: found 40.5%, calc. 42%; Cl: found37.5%, calc. 38%) may be 70% based upon stannous chloride originallycharged to the reaction vessel.

EXAMPLE 2 In this example, the same reactants may be used as for Example1, except that, 150 parts of toluene diluentsolvent may be added to thereaction mixture. After completion of the reaction, the fractionsobtained on distillation may be found to be as follows:

(a) 215 parts of unreacted butyl chloride and toluene containing 4 partsof butyltin trichloride, recovered up to about 150 C.;

(b) 210 parts of butyltin trichloride recovered at 130 C. at 8 mm. Hg;

(c) 41 parts of stannous chloride as residue.

The yield of butyltin trichloride may be 75% based on the anhydrousstannous chloride originally charged to the reaction vessel.

EXAMPLE 3 The process of Example 2 may be duplicated except that inplace of using aniline as the catalyst, 0.36 part (0.005 mole) of butylamine may be used as catalyst. There may be recovered from the reactionsystem 220 parts of butyltin trichloride having a boiling point of90-125 C./l0 mm. Hg representing a yield of 80% based upon stannouschloride originally charged to the reaction vessel.

Although this invention has been illustrated by reference to specificexamples, numerous changes and modifications thereof which clearly fallwithin the scope of the invention will be apparent to those skilled inthe art.

I claim:

1. The method of preparing organotin compounds RSnX by the reaction SnX+RX RSnX wherein R is a hydrocarbon group, Sn is tin, and X is an activehalogen which comprises reacting anhydrous SnX with RX in the presenceof an amine catalyst in a reaction mixture thereby forming RSnXmaintaining substantially equivalent amounts of SnX and RX in saidreaction mixture during said reaction; maintaining said reaction mixtureat 250 C. and autogenous pressure during said reaction; and separatingfrom said reaction mixture RSnX 2. The method of preparing organotincompounds RSnX as claimed in claim 1 wherein R is selected from thegroup consisting of alkyl, aryl, alkaryl, aralkyl, and cycloalkylgroups.

3. The method of preparing organotin compounds RSnX as claimed in claim1 wherein R is an alkyl group.

4. The method of preparing organotin compounds RSnX as claimed in claim1 wherein R is a lower alkyl group.

5. The method of preparing organotin compounds RSnX as claimed in claim1 wherein X is chlorine.

6. The method of preparing organotin compounds RSnX as claimed in claim1 wherein the amine catalyst is an alkyl amine.

7. The method of preparing organotin compounds RSnX as claimed in claim1 wherein the amine catalyst is selected from the group consisting oftriethyl amine, aniline, pyridine, and n-butyl amine.

8. The method of preparing organotin compounds RSnX as claimed in claim1 wherein said amine catalyst is present in said reaction mixture inamount of 0.01-2 mole percent of the amount of SnX present.

9. The method of preparing organotin compounds RSnX as claimed in claim1 wherein said amine catalyst is present in said reaction mixture inamount of 0.1-1 mole percent of the amount of SnX present.

10. The method of preparing organotin compounds RSnX by the reaction SnX+RX RSnX wherein R is a hydrocarbon group, Sn is tin, and X is an activehalogen which comprises reacting anhydrous SnX with RX in the presenceof an amine catalyst in a reaction mixture containing inertdiluent-solvent thereby forming RSnX maintaining substantiallyequivalent amounts of SnX- and RX in said reaction mixture during saidreaction; maintaining said reaction mixture at 100250 C. and autogenouspressure during said reaction; and separating RSnX from said reactionmixture RSnX 11. The method of preparing organotin compounds RSnX asclaimed in claim 10 wherein said solvent has a boiling point of 250 C.

12. The method of preparing organotin compounds RSnX as claimed in claim10 wherein said diluent-solvent is a hydrocarbon.

13. The method of preparing organotin compounds RSnX as claimed in claim12 wherein said diluent-solvent is an aliphatic hydrocarbon.

14. The method of preparing butyltin trihalide which comprises reactinganhydrous SnX with butyl halide in the presence of an amine catalystthereby forming butyltin trihalide; maintaining substantially equivalentamounts of SnX and butyl halide in said reaction mixture during saidreaction; maintaining said reaction mixture at 250 C. and autogenouspressure during said reaction; and separating butyltiu trihalide fromsaid reaction mixture.

No references cited.

TOBIAS E. LEVOW, Primary Examiner.

W. F. W. BELLAMY, Examiner.

1. THE METHOD OF PREPARING ORGANOTIN COMPOUNDS RSNX3 BY THE REACTIONSNX2+RX$RSNX3 WHEREIN R IS A HYDROCARBON GROUP, SN IS TIN, AND X IS ANACTIVE HALOGEN WHICH COMPRISES REACTING ANHYDROUS SNX2 WITH RX IN THEPRESENCE OF AN AMINE CATALYST IN A REACTION MIXTURE THEREBY FORMINGRSNX3; MAINTAINING SUBSTANTIALLY EQUIVALENT AMOUNTS OF SNX2 AND RX INSAID REACTION MIXTURE DURING SAID REACTION; MAINTAINING SAID REACTIONMIXTURE AT 100*-250*C. AND AUTOGENOUS PRESSURE DURING SAID REACTION; ANDSEPARATING FROM SAID REACTION MIXTURE RSNX3.